1. Field of the Invention
This invention relates to a bath composition comprising a complex powder of a water-soluble polymer and a water-soluble aluminum salt which dissolve easily in bath water without producing agglomerates. Such bath compositions, when dissolved and dispersed in bath water, can simulate an alum hot spring, and provide, upon bathing, a refreshing and comfortable feeling of dryness to the skin. The present invention also pertains to a bath containing such a bath composition; and a method of bathing using such a bath composition.
2. Discussion of the Background
Aluminum sulfate and its related salts, exemplified by alum and similar salts, are known components of alum springs. These compounds suppress perspiration and provide a refreshing and comfortable feeling of dryness to the skin, as a result of their astringent property.
Recently, people have sought to enjoy the sensation of a natural hot spring in their home and various bath compositions or bath additives which contain components of natural hot springs have been developed to provide such a sensation. However, when salts of aluminum sulfate have been incorporated into a bath composition and dispersed in water to form an artificial alum spring, the salts react with other water-soluble inorganic salts contained in the bath composition to produce water-insoluble white particles or agglomerates. These agglomerates mar the appearance of the bath water. Moreover, since these agglomerates are hard particles, a disagreeable skin sensation results. If the salts of aluminum sulfates are incorporated into an effervescent bath composition containing a carbonate and a neutralizer, then water-insoluble white agglomerates of even larger size are produced. These agglomerates float on the surface of bath water because of the carbon dioxide gas generated in the agglomerates. Such bath water has a very disagreeable appearance.
Pigments are also commonly used in bath compositions. Water-insoluble pigments, such as, titanium oxide and similar pigments, make bath water opaque when, as components of a bath preparation, they are added to bath water. The opaque bath water more effectively simulates the feeling of a natural hot spring. Moreover, since titanium oxide and similar pigments are in the form of powders, they provide a comfortable dry feeling.
When salts of aluminum sulfates and water-insoluble pigments are blended in a bath composition for use in an artificial alum spring (hereinafter referred to as alum bath or alum bath water), the pigments cohere and precipitate due to the flocculating action of the water-soluble aluminum salts. This results in clear bath water. If titanium oxide or similar pigments and salts of aluminum sulfates are incorporated into an effervescent bath preparation containing a carbonate and a neutralizer, then water-insoluble white wads are produced, which float on the surface of the bath water (because of carbon dioxide gas). This gives a disagreeable appearance to the bath water. These white wads not only destroy the sensation of a hot spring, but also impart an unpleasant skin sensation.
To avoid such problems in the preparation of an opaque alum bath, the salts of aluminum sulfates must be prevented from forming water-insoluble materials in the presence of other water-soluble inorganic salts. This can be achieved by making the pH of the bath water either strongly acidic, with a pH not higher than 4, or strongly basic, with a pH not lower than 10.5. However, such strongly acidic or strongly basic bath water injures the skin and damages the bath tub and heating device.
Therefore, there remains a need for a bath composition which dissolves and disperses easily into bath water and provides an alum bath which does not damage skin, tub or heating device.